Biological microscope. Forensic microscope. Desktop SEM

Image Credit: Keyence | Leica | NanoScience Instruments 

Microscopes are instruments that magnify images of small objects using lenses as the locus of magnification.  Specialty microscopes are different from garden-variety microscopes in that they are designed for specific applications, or they use specialized techniques or technologies to produce magnification. 

Application

Specialty microscopes application types include life sciences, gemology and metallurgical microscopes, toolmaking, forensics, and semiconductor inspection.

• Specialty microscopes for biological and life sciences applications include those that transmit light or environmental scanning electron microscopes (SEM). 
• Gemological microscopes use polarized light with lower magnifying powers to allow for brighter, sharper images combined with a wide field of view.
• Metallurgical microscopes are often inverted for viewing the bottom of a sample with lower magnifying powers to allow for brighter, sharper images combined with a wide field of view.
• Tool making specialty microscopes are often used for dimensional measurement with lower magnifying powers to allow for brighter, sharper images combined with a wide field of view. 
• Forensic microscopes are often hands-free, binocular microscopes with lower magnifying powers to allow for brighter, sharper images combined with a wide field of view. 

• Semiconductor inspection specialty microscopes used to study the layers in a semiconductor wafer or fabricated IC components.  This inspection type calls for greater precision and throughput.

Microscope Type

Some specialty microscopes are differentiated by their methods of producing magnification. 

• Acoustic and ultrasonic microscopesuse sound waves to create images of the sample.  These types of microscopes can be used to examine delimitations, cracks and other anomalies nondestructively. 
• Microwave microscopes use electromagnetic radiation, which has a long wavelength (between 1 mm and 30 cm), to study specimens.
• Portable field specialty microscopes are designed for use outside of the laboratory setting.  They may have a portable energy source, such as a battery, or they may use natural light for illumination.  These microscopes are generally lightweight and handheld.
• Scanning probe and atomic force (SPM / AFM) microscopes are used to study surface features by moving a sharp probe over the object's surface (e.g., the scanning tunneling microscope).  Atomic force microscopes enable the user to image the topography of a sample, and to monitor simultaneously ultrasonic surface vibrations in the MHz range. For detection of the distribution of the ultrasonic vibration amplitude, a part of the position-sensing light beam reflected from the cantilever is directed to an external knife-edge detector.

• Confocal specialty microscopes or laser microscopes use laser light to image one plane of a specimen at a time.

Grade

The grade of the microscope determines the cost and quality of the device.

Specifications

There are many specifications to consider when selecting a microscope. Important specifications for selecting a specialty microscope include the total magnification and the resolution.

• Total magnification- The primary purpose of a microscope is to magnify a sample. Magnification is defined as the ratio of the size of the image seen to the corresponding object. The total magnification is determined by multiplying the magnification capability of the eyepiece lens by that of the objective lens.

• Resolution- By definition, resolution is the ability of a lens to distinguish the fine details of the specimen being viewed. It is the minimum distance between two lines or points in the object that are perceived as separate by the human eye.

Resources

Buying Microscopes

Read GlobalSpec's How to Select Microscopes for more infromation.